The Purification process begins as the transfer tank of clarified lysate from the Recovery process is connected to the inlet pump on the Chromatography skid.
The first Chromatography step in our GFP purification process is Anion-Exchange. At this point in the process, the pH of the clarified lysate is about eight-point-zero, which means that the protein is negatively charged. Because it is negatively charged, GFP will bind to the positively charged anion exchange resin.
The pump draws the lysate from the vessel...past the first conductivity sensor and pressure sensor...and through the zero-point-four-five micron pre-filter. The pre-filter removes any residual cell debris or other particulates that may have contaminated the solution.
If the pre-filter begins to clog, the pressure sensor at the inlet side of the filter will register a rising pressure...and the controller will signal the need for a filter change.
After pre-filtering and before the column, the lysate passes through a flow meter...
and an air sensor. Then, as the lysate passes over the resin beads, the negatively charged protein attaches to the positively charged beads.
The solution leaving the column passes a UV optical density sensor, a conductivity sensor and a pH sensor. The optical density sensor's low readings confirm that the GFP is not in the solution, so the outlet valve sends the solution to waste.